By 'use it immediately' if you mean rolling back to snapshot, yes you can do that. For ex: You've taken a snapshot --> made some changes to the VM and then decide to discard those changes, you revert using the snapshots.
If you are looking for anything specific or the concern is totally different, please share more details
Hope that helps.
sorry for make you confused. I mean to continue using the VM.
for example, after I snapshot before installing software. Can I immediately install it and revert if I make mistake? or I have to wait until snapshot complete then I will able to install.
thanks all for reply
Wait for the snapshot creation task to complete.
Note: If you take a memory snapshot, it will take little longer than as it has to snap the memory state of the VM. Non-memory snapshot will be quick, VM will be powered off when you revert to snapshot.
Please refer 'Process to Create snapshot' section here for more information --> https://kb.vmware.com/s/article/1015180
It's an important point to know about the snapshot before doing everything: When you take a snapshot of your VM, this operation cuts the VMDK into the two separate VMDK files (delta and main) in a parent-child relation to let the VM's real-time operations continue their working. Especially in the case of VM Backup execution, it's very useful.
for more investigation about the snapshot generation, read the following post in my personal blog: